Asparagus will grow in full sunshine and you can harvest some of the spears the first season from your three year old crowns. Don't harvest them all, though. The spears will develop into ferny foliage which will help the crowns develop extensive root systems. Cut spears when they grow about 6 to 8 inches tall; their tips should still be tight. Take only thicker spears; spindly ones should be left alone. Snap asparagus off at the soil line, or use a sharp knife to slice through the spear at an angle an inch or two below the soil surface. Be careful not to damage spears not yet emerged from the soil.